Machine for separating ground wood pulp into different grades



(No Model.)

E. P. MILLARD. MACHINE PUR SEPARATING GROUND WOOD PULP INTO DIFFERENTGRADES.

No.,457,089. Patented Aug. 4, 1891.

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UNTTED STATES PATENT OFFICE.

EDIVARD F. MILLARD, OF JACKSON, MICHIGAN.

MACHINE FOR SEPARATING GROUND WOOD PULP INTO DIFFERENT GRADES.

SPECIFICATION forming part of Letters Patent No. 457,089, dated August4, 1891. Application filed October l1l 1890. Serial No. 367,847. (Nomodel.)

To all w/'Lom it may concern:

Be it known that I, EDWARD F. MILLARD, of Jackson, in the county ofJackson and State of Michigan, have invented a new and useful Machinefor Separating Grou nd food Pulp into Different Grades, of which theVfollowing isa specification.

In the drawings hereto attached and made a part of this specification,Figure 1 is a longitudinal section of the screening-machine. Fig. 2 is adetached perspective view of the head at the discharge end of the screenand a dipper attached thereto. Fig. 3 is a vertical section of theseparating-screen and the box in which it runs. Fig. 4 is a similar viewof the washing-screen.

The same letters are employed in all of the figures in the indication ofidenticalparts.

A is a cylinder or polygon covered, preferably, with perforated sheetmetal. It is hung upon hollow trunnions B and B', carried on the ends ofthe box C. VThe pulpliquor is introduced through the pipe D andhollowtrunnion B into the interior of the screen. That screen is revolved byany suit- `able and convenient driving belt or gearing,

and it has in its interior a conveyer, preferably a worm E, formed by aspiral iiange projecting inwardly from the periphery of the screen andso formed that by the revolution of the screen the spiral fiange actingon the material in t-heliquor will cause it to pass from the head slowlytoward the tail of the machine, carrying along toward the tail sliversand other particles which do not go through the screen. It will beobserved that the effectof this conveyeris to cause the body of the pulpinside of the screen to be moved toward the tail with a gentle motion,the prime object of my invention being to avoid any throwing or dashingof the pulp-liquor against the screen, as has been heretofore practicedin other machines, my object being to avoid any violent force whichwould cause the coarser particles of the pulp tobe driven through themeshes of the screen. Another conveyer F of smaller diameter is attachedinside of the conveyer E, as shown in the drawings, Fig. l. At its lowerend is the dipper G, which in revolving gathers up the water and solidparticles contained in it at the tail end of the screen and lifts it upand pours it into the opening' in the interior of the hollow trunnion B.Both the conveyers are formed of spiral strips, one attached at theperiphery of the cylinder, internally, to act upon material near thescreen and move it toward the tail of the screen, the other merelyskimming the surface and acting upon materalloating on the surface. Thisinternal conveyer F is suspended at the ends at the inlet and outletopenings and both revolve with the screen. discharge-opening andisformed concave in cross-section, and curved so as to form a scoop ordipper for gathering the splinters and delivering them into the outlet.If necessary, a similar clipper may be formed on the tail end oftheouter conveyer to similarly discharge into the outlet.

Other devices in use may be substituted for elevating solid matter atthe tail end, delivering it into the outlet. As that feature is old, noclaim is made upon it separately, and it need not be more particularlydescribed.

The level of the liquor in the interior of the screen is determined bythe dams H H', forming a trough or vat within the box Q. The dams H, ofwhich there may be two, as shown, or only one, if preferred, areextended up to about the level of the bottom of the educ'- tion-pipe B',so that the lower half (nearly) of the screen will run in the liquorwhich contains the line particles of pulp, and as fresh liquor issupplied through the pipe D the Water together with the fine pulp willflow out through the perforation of the screen and into the trough orvat formed by the dams H H', or I-I alone if only one is used. The otherside of the trough in that case would be formed in the side of theexternal box C. As the water continues to pour in, after passing throughthe perforations in the screen and into the trough below it, it williiow over the dams II H', or the single dam if only one is used, into adischarge-trough formed between the dam H and wall C, whence it willflow away to the place where it is to be used..

The portion in which the cylinder wallows, between the dams HH', Fig.3,I shall designate the vat and indicate it by the letter X. The portioninto which the overflow isk dis- The conveyer F extends into the IDOcharged, between the dam or dams and the side C of the box, I willdesignate as the trough and indicate it by the letter Z, it beingunderstood that there may be one or two of these, according to thenumber of dams. The liquor, therefore, being maintained at the level ofthe hollow trunnions, nearly half of the periphery of the screen will becontinually submerged, and the worm E will of course extend as deep asthe screen, while the worm F will only dip a few inches into the top ofthe liquor. The function of the worm E is to engage the slivers andcoarse impurities which may be floating on the surface of the liquor andmove them steadily toward the tail of the screen, where they 'will becaught up by the dipper G, lifted, and brought into the hollow trunnionB. As there will be some ine pulp remaining and adhering to the surfacesof these slivers, they should be subjected to a washing operation, whichis carried on in another screen, which may be either directly attachedto the eduction-pipe of the screen or maybe more remote, a pipe leadingfrom one to the other.

I is the washer, which, as illustrated, is a rotating screen attached toone end of the hollow trunnion B and at the other resting on a standardK, and below the screen l is a trough L, the top of which is at a levelwith the bottom of the screen, and itis inclosed in the walls of avat M,which extends up above the water-level. Within the washer-screenl isplaced one or more perforated pipes O, through which water underpressure is discharged inside of the screen I for the purpose of washing off whatever fine pulp may be adhering to the surface of the slivers,

f which itdrives off through theintersticesof the screen into the troughL, overflowing which,

it escapes into the trough between L and M, and thence is dischargedinto the same place to which the iine pulp taken out through the screenE is delivered. A pipe P, perforated with fine holes, is also arrangedalong the outer surface of the screen A, drivingthe jets of wateragainst its surface for the purpose of pressing back any particles thatmight stick in the interstices of the screen A.

What I claim as my invention, and desire to secure by Letters Patent,is-

l. In combination with a rotary screen carried upon tubular journals, acouveyer which gives forward impulse to the pulpliquor within the screentoward the tail, a Vat in which the screen is partially submerged, atrough into which the tine pulp overflows after passing through thescreen, and an elevator which lifts the tailings from' the interior ofthe screen and delivers them into the discharge-opening, substantiallyasset forth.

2. The combination of a rotary screen, a tank in which itis partiallysubmerged, an exterior receptacle for the overiiow, an inlet and adischarge, with a second screen into which the tailings are discharged,and means for further washing the tailings for separating the adheringfine pulp from the coarse slivers, substantially as set forth.

3. In combination with arotary and partially-submerged screen,axially-located inlet and outlet openings and a centrally-suspendedspiral conveyer F, skimming the Heating slivers toward and elevatingthem into the outlet-opening, substantially as set forth.

4. In combination with a partially submerged screen, an outer worm E andan inner worm F, substantially as set forth.

In testimony whereof I have hereunto subscribed my name in the presenceof two attesting witnesses.

EDNVARD F. MILLARD.

Witnesses:

AUGUSTUS GooDALE, S. S. TROWBRIDGE.

